Retractable sensor for an alarm system

Abstract

A retractable sensor assembly for use with an alarm system to prevent theft of valuable products while eliminating the problem of entangled and unsightly sensor cords is disclosed. The retractable sensor allows the user to grasp the product and pull it to a comfortable position. The invention consists of a housing, a retraction means contained in the housing, a sensor having two states, 1) secured when attached to the product and 2) unsecured when detached from the product, a multiconductor cable having a first end connected to the sensor, cooperating with the retraction means and a second end extending out of the housing, where the retraction means urges the sensor to the housing, yet allows the sensor to be pulled from the housing when an external force is exerted on the sensor, while maintaining a continuous electrical path from the first, sensor end of the cable to the second end of the cable.

We claim:  
     
       1. A retractable sensor assembly, as used with an alarm system, comprising; 
       a housing;  
       means for retraction contained in said housing;  
       a sensor having two states, 1) secured when attached to a product and 2) unsecured when detached from said product, said sensor being outside the housing;  
       a multiconductor cable, having a first end attached to the sensor then extending into the housing, cooperating with the retraction means and a second end extending out of the housing;  
       said retraction means urging the cable into the housing and thereby urging the sensor to the retraction means, yet allowing the sensor to be pulled from the housing when an external force is exerted on the sensor, while maintaining a continuous electrical path from the first, sensor end of the cable to the second end of the cable; and  
       means for connecting said second end of the cable to an alarm system able to detect if said sensor is in the secured or unsecured state,  
       whereby a user can grasp and pull on a product attached to the sensor to place the product in a comfortable position, but if the user detaches the product from the sensor the alarm system detects the unsecured state.  
     
     
       2. The retractable sensor assembly of  claim 1  wherein said sensor has an indicating means for indicating the state of the sensor. 
     
     
       3. The retractable sensor assembly of  claim 2  wherein said indicating means is a light-emitting diode. 
     
     
       4. The retractable sensor assembly of  claim 1  wherein said multiconductor cable is a phone cord. 
     
     
       5. The retractable sensor assembly of  claim 1  wherein said retraction means includes; 
       a spool mounted in the housing upon which said multiconductor cable is wound; and  
       biasing means operatively associated with said spool in said housing for urging said spool in a direction to wind the cable on the spool, yet to permit unwinding of the cable when an external force is exerted on the sensor.  
     
     
       6. A retractable sensor assembly, as used with an alarm system, comprising; 
       a housing;  
       a pulley mounted for rotation in said housing, having a pair of hubs, a sensor hub and an alarm system hub, and a disk between the sensor and the alarm system hub has a hole;  
       a multiconductor cable wound about the sensor hub through said hole in said disk and then wound around the alarm system hub of said pulley, the cable having opposite near and remote ends;  
       a sensor, outside the housing, connected to the remote end of said cable and being attachable to a product, said sensor having two states, 1) secured when attached to the product and 2) unsecured when detached from the product, and the sensor including means for electrically connecting or disconnecting conductors in said cable according to the state of the sensor;  
       biasing means operatively associated with said pulley in said housing for urging said pulley and the pair of hubs in a direction to wind the cable around the sensor hub and thereby pull the sensor to the housing yet to permit the sensor to extend from the housing when an external force is exerted on the sensor; and  
       a connector, outside the housing, attached to the near end of the cable, for connecting to an alarm system,  
       whereby a user can grasp and pull on a product attached to the sensor to place the product in a comfortable position, but if the user detaches the product from the sensor the alarm system detects the unsecured state.  
     
     
       7. The retractable sensor assembly of  claim 6  wherein said sensor includes a means for visually indicating whether the sensor is in the secured or unsecured state. 
     
     
       8. The retractable sensor assembly of  claim 7  wherein said indicating means is a light-emitting diode. 
     
     
       9. The retractable sensor assembly of  claim 6  in combination with a product and including means for attaching the sensor to the product so that the sensor is in the secured state. 
     
     
       10. The retractable sensor assembly of  claim 9  wherein the sensor and cable are the only elements connecting between the product and housing. 
     
     
       11. A retractable cable assembly, as used with an alarm system, comprising; 
       a housing;  
       means for retraction contained in said housing;  
       a multiconductor cable, having a first end attached to a sensor attachable to a product then extending into the housing, cooperating with the retraction means and a second end extending out of the housing, said sensor having two states,  1 )  secured when attached to the product with at least two conductors of the cable electrically connected and  2   )  unsecured when detached from the product with said at least two conductors electrically disconnected;    
       said retraction means urging the cable into the housing and thereby urging the first end connected to a product  the sensor to the retraction means, yet allowing the first end to be pulled from the housing when an external force is exerted on the first end, while maintaining a continuous electrical path in said at least two conductors from the first end of the cable to the second end of the cable; and  
       means for connecting the second end of the cable to an alarm system which detects a) a  the secured state with the electrical path continuous between the first and second ends of the cable  at least two conductors of the cable electrically connected and b) an unsecured state with the continuity of the electrical path between the first and second cable ends broken  at least two conductors of the cable electrically disconnected,  
       whereby a user can grasp and pull on a product attached to the first cable end to place the product in a comfortable position, but if the user breaks the continuity of the electrical path  electric connection of the at least two conductors of the cable the alarm system detects the unsecured state.  
     
     
       12. A retractable cable assembly, as used with an alarm system, comprising; 
       
         a housing;  
       
       
         a cable having first and second conductors extending between opposite first and second ends of said cable;  
       
       
         means for attaching said cable first end to a product;  
       
         means for electrically connecting said first and second conductors at said first end of said cable whereby  1   )  said first and second conductors form an alarm loop extending from said cable second end through said first conductor to said cable first end and back through said second conductor to said cable second end when said attaching means attach said cable to a product and  2   )  said alarm loop is broken by detaching said cable from a product;    
       
         a connector for connecting said cable second end to an alarm system responsive to any break of the alarm loop; and  
       
       
         a retracting mechanism in said housing continuously urging the cable first end toward the housing yet allowing the cable first end to be pulled away from the housing when an external force is exerted on the cable first end.  
       
     
     
       13. The retractable cable assembly of  claim 12 , wherein said retracting mechanism continuously urges the cable first end toward the housing, whereby a user can grasp and pull on a product attached to the cable first end to place the product in a comfortable position with a minimum amount of cable extending from said housing.  
     
     
       14. The retractable cable assembly of  claim 13 , wherein said retracting mechanism comprises: 
       
         a pulley mounted for free rotation relative to said housing and including a sensor hub and an alarm system hub separated by a disk, said disk having a hole therein, whereby said cable extends from said cable first end into said housing where it winds around said sensor hub then extends through said pulley disk hole and winds about said alarm system hub then extends from said housing to said cable second end; and  
       
       
         a spring continuously biasing said pulley toward winding said cable onto said sensor hub.